Process to make base oil from thermally cracked waxy feed using ionic liquid catalyst

ABSTRACT

We provide a process for making a base oil, comprising: a) selecting an olefin feed produced by thermal cracking of a waxy feed; b) oligomerizing the olefin feed in an ionic liquid oligomerization zone at a set of oligomerization conditions to form an oligomer; and c) alkylating the oligomer in the presence of an isoparaffin, in an ionic liquid alkylation zone, at a set of alkylation conditions to form an alkylated oligomeric product having a kinematic viscosity at 100° C. of 6.9 mm 2 /s or greater, a VI of at least 134, and a Bromine Number of less than 4. We provide a process to make base oil from an olefin feed produced in a FCC unit. We also provide a process to make two or more viscosity grades of base oil from an olefin feed produced by thermal cracking of a waxy feed.

This application is a continuation in part of U.S. patent applicationSer. No. 11/316,154, filed Dec. 20, 2005, now U.S. Pat. No. 7,572,943;U.S. application Ser. No. 11/316,155, filed Dec. 20, 2005, now U.S. Pat.No. 7,572,944; U.S. application Ser. No. 11/316,157, filed Dec. 20,2005, now U.S. Pat. No. 7,569,740; U.S. application Ser. No. 11/316,628,filed Dec. 20, 2005, now U.S. Pat. No. 7,576,252; and Ser. No.12/261,388, filed Oct. 30, 2008: and herein incorporated in theirentireties.

This application is related to a co-filed application, titled “PROCESSTO MAKE BASE OIL FROM FISCHER-TROPSCH CONDENSATE;” herein incorporatedin its entirety.

SUMMARY OF THE INVENTION

We provide a process for making a base oil, comprising: a) selecting anolefin feed produced by thermal cracking of a waxy feed; b)oligomerizing the olefin feed in an ionic liquid oligomerization zone ata set of oligomerization conditions to form an oligomer; and c)alkylating the oligomer in the presence of an isoparaffin, in an ionicliquid alkylation zone, at a set of alkylation conditions to form analkylated oligomeric product having a kinematic viscosity at 100° C. of6.9 mm²/s or greater, a VI of at least 134, and a Bromine Number of lessthan 4.

We provide a process for making a base oil, comprising: a) oligomerizingat least one olefin in an olefin feed produced in a FCC unit to producean oligomerized product boiling in the middle distillate range; and b)alkylating the oligomerized product in an ionic liquid alkylation zone,at a set of alkylation conditions, to form an alkylated oligomericproduct having a kinematic viscosity at 100° C. of 6.9 mm²/s or greaterand a VI of at least 134.

We also provide a process to make two or more viscosity grades of baseoil, comprising: a) alkylating and oligomerizing an olefin feed producedby thermal cracking of a waxy feed with an acidic ionic liquid catalystin an alkylation zone to produce an alkylated oligomeric product; and b)separating out two or more viscosity grades of base oil from thealkylated oligomeric product, wherein at least one of the two or moreviscosity grades of base oil has:

i. a kinematic viscosity at 100° C. of 6.9 mm²/s or greater,

ii. a VI of at least 134, and

iii. a Bromine Number of less than 4.

DETAILED DESCRIPTION OF THE INVENTION

In the present application the terms base oil, lubricant base oil,lubricant blendstock, and lubricant component are used to mean lubricantcomponents that can be used to produce a finished lubricant.

The base oil is an alkylated oligomeric product. It can have a kinematicviscosity at 100° C. from about 1.5 mm²/s to 30 mm²/s. In someembodiments the base oil has a kinematic viscosity of 6.9 mm²/s orgreater. In other embodiments the process makes two or more viscositygrades of base oil. The two or more viscosity grades of base oil havekinematic viscosities at 100° C. from about 1.5 mm²/s to 30 mm²/s.Kinematic viscosity is measured by ASTM D 445.

A viscosity grade of base oil is base oil that differs from anotherviscosity grade of base oil by having a difference in kinematicviscosity at 100° C. of at least 0.5 mm²/s. Examples of differentviscosity grades of base oil are XXLN, XLN, LN, MN, and HN. An XXLNgrade of base oil, when referred to in this disclosure, is a base oilhaving a kinematic viscosity at 100° C. between about 1.5 mm²/s andabout 2.3 mm²/s. An XLN grade of base oil is a base oil having akinematic viscosity at 100° C. between about 2.3 mm²/s and about 3.5mm²/s. A LN grade of base oil is a base oil having a kinematic viscosityat 100° C. between about 3.5 mm²/s and about 5.5 mm²/s. A MN grade ofbase oil is a base oil having a kinematic viscosity at 100° C. betweenabout 5.5 mm²/s and about 10.0 mm²/s. A HN grade of base oil is a baseoil having a kinematic viscosity at 100° C. above 10 mm²/s. Generally,the kinematic viscosity of a HN grade of base at 100° C. will be betweenabout 10.0 mm²/s and about 30.0 mm²/s.

“Waxy feed” is a feed or stream comprising hydrocarbon molecules with acarbon number of C20+ and having a boiling point generally above about600° F. (316° C.). A waxy feed contains at least 40 wt % normalparaffins, and in some embodiments may contain at least 50 wt % normalparaffins, or at least 75 wt % normal paraffins. The wt % normalparaffins are measured by a method described later in thisspecification. In some embodiments a major portion of the feed shouldboil above 650° F. In one embodiment at least 80 wt % of the feed willboil above 650° F., and in another embodiment at least 90 wt % will boilabove 650° F. Waxy feeds typically will have an initial pour point above0° C., or in other embodiments, above 10° C. Pour point is measured byASTM D 5950-02 (Reapproved 2007).

The waxy feeds useful in the processes disclosed herein may be syntheticwaxy feedstocks, such as Fischer Tropsch waxy hydrocarbons, or may bederived from natural sources. Accordingly, the waxy feeds to theprocesses may comprise Fischer Tropsch derived waxy feeds, petroleumwaxes, waxy distillate stocks such as gas oils, lubricant oil stocks,high pour point polyalphaolefins, foots oils, normal alpha olefin waxes,slack waxes, deoiled waxes, microcrystalline waxes, and mixturesthereof.

Oligomerization of two or more olefin molecules results in the formationof an olefin oligomer that generally comprises a long branched chainmolecule with one remaining double bond. In some embodiments theprocesses provide an improved way to reduce the concentration of doublebonds and at the same time enhance the quality of the desired fuel orlubricant. The processes reduce the amount of hydrofinishing that may beneeded to achieve a desired product with low olefin concentration. Theolefin concentration can be determined by Bromine Index or BromineNumber. Bromine Number can be determined by test ASTM D 1159. BromineIndex can be determined by ASTM D 2710. Test methods D 1159 and ASTM D2710 are incorporated herein by reference in their entirety. BromineIndex is effectively the number of milligrams of Bromine (Br₂) thatreact with 100 grams of sample under the conditions of the test. BromineNumber is effectively the number of grams of bromine that will reactwith 100 grams of specimen under the conditions of the test.

In one embodiment, HCl or a component that directly or indirectlysupplies protons is added to either or both the oligomerization zone orthe alkylation zone. Although not wishing to be limited by theory it isbelieved that the presence of a Brönsted acid such as HCl greatlyenhances the acidity and, thus, the activity of the ionic liquidcatalyst.

In one embodiment, the lubricant base oil or lubricant blendstock hasreduced levels of olefins without hydrogenation or with minimalhydrofinishing. In some embodiments, the value of the resultant olefinoligomers is raised by increasing the molecular weight of the oligomerand increasing the branching by incorporation of isoparaffin groups intothe oligomers' skeletons. These properties can both add significantvalue to the product, particularly when starting with a highly linearhydrocarbon. In some embodiments, the products can have a combination ofhighly desirable and novel qualities for a lubricant component or baseoil, including having a very high VI with a very low cloud point whilealso having a fairly wide boiling range.

In some embodiments the alkylated oligomeric product has a low cloudpoint. The cloud point can be less than −30° C., less than −40° C., lessthan −45° C., or less than −50° C. In the past it has been verydifficult to obtain low cloud points when making base oils from waxyfeeds.

In one embodiment the alkylated oligomeric product has a broad boilingrange. A broad boiling range is a difference between the T90 and T10boiling points of at least 225° F. by SIMDIST. In some embodiments thealkylated oligomeric product has a difference between the T90 and T10boiling points of at least 225° F., 250° F., 275° F., or 300° F. Becauseof the broad boiling range, the alkylated oligomeric product maycomprise two or more viscosity grades of base oil. The differentviscosity grades of base oil in the alkylated oligomeric product may beseparated by vacuum distillation. One of the viscosity grades of baseoil may be a distillate bottoms product.

Sometimes there is an increased demand for one viscosity grade of baseoil. In some embodiments, the set of oligomerizing conditions or set ofalkylating conditions are selected to optimize a yield of one of the twoor more viscosity grades of base oil. For example the ratio of anisoparaffin to an olefin can be adjusted up to favor more alkylation andless oligomerization, such that a yield of a lighter viscosity grade ofbase oil is increased. Alternatively, the amount of a Brönsted acid ineither the oligomerization zone or the alkylation zone may be adjustedto optimize a yield of one of the two or more viscosity grades of baseoil.

In one embodiment the oligomerizing is dimerizing. In another embodimentthe oligomerizing brings together more than two olefins, so it is morethan dimerizing.

In one embodiment, the oligomerized product boils in the middledistillate range. A “middle distillate” is a hydrocarbon product havinga boiling range between 250° F. and 700° F. (121° C. and 371° C.). Theterm “middle distillate” includes the diesel, heating oil, jet fuel, andkerosene boiling range fractions. It may also include a portion ofnaphtha or light oil. A “naphtha” is a lighter hydrocarbon producthaving a boiling range between 100° F. and 400° F. (38° C. and 204° C.).

In one embodiment the oligomerized product has lower amounts ofheteroatoms than in the olefin feed. Examples of heteroatoms arenitrogen, sulfur, and oxygen. Lower amounts of heteroatoms are desiredin base oil. It is also desirable to have lower amounts of heteroatomsin some embodiments, as they can interfere with the alkylating step ofthe process.

In one embodiment the process uses an ionic liquid catalyst to alkylatean oligomerized olefin with an isoparaffin under relatively mildconditions. For example, in one embodiment the heat of reaction duringthe alkylating remains at 100° C. or less, at 75° C. or less, at 50° C.or less, or at 25° C. or less. The alkylation optionally can occur undereffectively the same conditions as oligomerization. This finding thatalkylation and oligomerization reactions can occur using effectively thesame ionic liquid catalyst system and optionally under similar or eventhe same conditions can be used to make a highly integrated, synergisticprocess resulting in an alkylated oligomer product having desirableproperties. Also in a particular embodiment the alkylation andoligomerization reactions can occur simultaneously under the sameconditions.

In some embodiments the ionic liquid oligomerization zone, or the ionicliquid alkylation zone, comprises an acidic chloroaluminate ionic liquidcatalyst. In some embodiments both the ionic liquid oligomerization andthe ionic liquid alkylation zones comprise an acidic chloroaluminateionic liquid catalyst. In some embodiments, the same acidicchloroaluminate ionic liquid catalyst is used in both zones.

In some embodiments the acidic chloroaluminate ionic liquid catalyst isused in the presence of a Brönsted acid. The Brönsted acid may be ahalohalide such as hydrogen chloride. Other promoters such as alkylhalides or metal halides may be added to the oligomerization oralkylation zones.

The oligomerization reaction and the alkylation reaction can beperformed concurrently or separately. An advantage of combining theoligomerization and alkylation is lower capital and operating costs. Anadvantage of the 2 step process (oligomerization followed by alkylationin a separate zone) is that the two separate reaction zones can beoptimized independently. Thus the conditions for oligomerization zonescan be different than the alkylation zone conditions. Also the ionicliquid catalyst can be different in the different zones. For instance,it may be preferable to make the alkylation zone more acidic than theoligomerization zone. This may involve the use of an entirely differentionic liquid catalyst in the two zones or one of the zones can bemodified, for example, by the addition of a Brönsted acid to thealkylation zone.

In one embodiment, the ionic liquid catalysts used in the alkylationzone and in the oligomerization zone are the same. This helps save oncatalyst costs, potential contamination issues, and provides synergyopportunities in the process.

In some embodiments, the process produces a product having a very lowcloud point and a very high VI. Cloud Point can be determined by ASTM D2500. VI can be determined by ASTM D 2270. ASTM test methods D 2500 andD D2270 are incorporated by reference herein in their entirety.

In the present application, distillation data was generated for severalof the products by SIMDIST. SIMDIST involves the use of ASTM D 6352 orASTM D 2887 as appropriate. ASTM D 6352 and ASTM D 2887 are incorporatedherein by reference in their entirety. Distillation data can also begenerated using ASTM D86 which is incorporated herein by reference inits entirety.

Ionic Liquids

Ionic liquids are a class of compounds made up entirely of ions and aregenerally liquids at ambient and near ambient temperatures. Often saltswhich are composed entirely of ions are solids with high melting points,for example, above 450° C. These solids are commonly known as ‘moltensalts’ when heated to above their melting points. Sodium chloride, forexample, is a common ‘molten salt’, with a melting point of 800° C.Ionic liquids differ from ‘molten salts’, in that they have low meltingpoints, for example, from −100° C. to 200° C. Ionic liquids tend to beliquids over a very wide temperature range, with some having a liquidrange of up to 300° C. or higher. Ionic liquids are generallynon-volatile, with effectively no vapor pressure. Many are air and waterstable, and can be good solvents for a wide variety of inorganic,organic, and polymeric materials.

The properties of ionic liquids can be tailored by varying the cationand anion pairing. Ionic liquids and some of their commercialapplications are described, for example, in J. Chem. Tech. Biotechnol,68:351-356 (1997); J. Phys. Condensed Matter, 5:(supp 34B):B99-B106(1993); Chemical and Engineering News, Mar. 30, 1998, 32-37; J. Mater.Chem., *:2627-2636 (1998); and Chem. Rev., 99:2071-2084 (1999), thecontents of which are hereby incorporated by reference.

Many ionic liquids are amine-based. Among the most common ionic liquidsare those formed by reacting a nitrogen-containing heterocyclic ring(cyclic amines), preferably nitrogen-containing aromatic rings (aromaticamines), with an alkylating agent (for example, an alkyl halide) to forma quaternary ammonium salt, followed by ion exchange with Lewis acids orhalide salts, or by anionic metathesis reactions with the appropriateanion sources to introduce the desired counter anionic to form ionicliquids. Examples of suitable heteroaromatic rings include pyridine andits derivatives, imidazole and its derivatives, and pyrrole and itsderivatives. These rings can be alkylated with varying alkylating agentsto incorporate a broad range of alkyl groups on the nitrogen includingstraight, branched or cyclic C₁₋₂₀ alkyl group, but preferably C₁₋₁₂alkyl groups since alkyl groups larger than C₁-C₁₂ may produceundesirable solid products rather than ionic liquids. Pyridinium andimidazolium-based ionic liquids are perhaps the most commonly used ionicliquids. Other amine-based ionic liquids including cyclic and non-cyclicquaternary ammonium salts are frequently used. Phosphonium andsulphonium-based ionic liquids have also been used.

Counter anions which have been used include chloroaluminate,bromoaluminate, gallium chloride, tetrafluoroborate, tetrachloroborate,hexafluorophosphate, nitrate, trifluoromethane sulfonate,methylsulfonate, p-toluenesulfonate, hexafluoroantimonate,hexafluoroarsenate, tetrachloroaluminate, tetrabromoaluminate,perchlorate, hydroxide anion, copper dichloride anion, iron trichlorideanion, antimony hexafluoride, copper dichloride anion, zinc trichlorideanion, as well as various lanthanum, potassium, lithium, nickel, cobalt,manganese, and other metal ions. In some embodiments, the ionic liquidcatalysts are acidic haloaluminates, such as acidic chloroaluminateionic liquid catalysts.

In some embodiments, the organic cations in the ionic liquid catalystscan be selected from the group consisting of pyridinium-based andimidazolium-based cations.

In one embodiment, the acidic chloroaluminate ionic liquid catalyst isan acidic pyridinium chloroaluminate. Examples are alkyl-pyridiniumchloroaluminates. In one embodiment, the acidic chloroaluminate ionicliquid catalyst is an alkyl-pyridinium chloroaluminate having a singlelinear alkyl group of 2 to 6 carbon atoms in length. One particularacidic chloroaluminate ionic liquid catalyst that has proven effectiveis 1-butyl-pyridinium chloroaluminate.

In one embodiment, 1-butyl-pyridinium chloroaluminate is used in thepresence of a Brönsted acid. Not to be limited by theory, the Brönstedacid acts as a promoter or co-catalyst. Examples of Brönsted acids areSulfuric acid, HCl, HBr, HF, Phosphoric acid, HI, etc. Other proticacids or species that directly or indirectly aid in supplying protonsmay also be used as Brönsted acids or in place of Brönsted acids.

The Feeds

In the process of the present invention one of the important feedstockscomprises an olefin feed produced by thermal cracking of a waxy feed.The olefinic group provides the reactive sites for the oligomerizationreaction as well as for the alkylation reaction. The olefin feed can bea fairly pure olefinic hydrocarbon cut or can be a mixture ofhydrocarbons having different chain lengths, and thus a wide boilingrange. The olefinic hydrocarbons in the olefin feed can be terminalolefins (alpha olefin) or can be internal olefins (internal doublebond). The olefinic hydrocarbons in the olefin feed can be eitherstraight chain, branched, or a mixture of both. The olefin feed caninclude unreactive diluents such as normal paraffins.

In one embodiment of the present invention, the olefin feed comprisesolefins in a range of C2 to C30, such as C2 to C7, C5 to C8, or C5 toC15. An example of an olefin feed with olefins in a range of C5 to C15is FCC naphtha. Another example is FCC gasoline. An example of an olefinfeed with olefins in a range of C2 to C5 or C2 to C7 is FCC gas. In someembodiments, certain ranges of olefins may be separated from theeffluent from a thermal hydrocracking process to optimize the processeconomics and to select a range of olefins that will produce a desiredalkylated oligomeric product. In some embodiments the olefin feedproduced by thermal cracking of a waxy feed will also compriseisoparaffins. In some embodiments, the isoparaffins may be separated outfrom the olefin feed. In other embodiments, they may not be separatedout from the olefin feed.

In one embodiment, the olefin feed is produced by thermal cracking of awaxy feed to make one or more thermally cracked hydrocarbons. Thermallycracked hydrocarbons may be cracked wax, such as cracked wax from aFischer-Tropsch (FT) process or thermally cracked petroleum wax. Aprocess for making olefins by cracking FT products is disclosed in U.S.Pat. No. 6,497,812 which is incorporated herein by reference in itsentirety. In one embodiment the olefin feed is produced by autothermallycracking a waxy hydrocarbon feedstream which has been selected toproduce high yields of linear alpha-olefins while enabling relativelyeasy separation of desired linear alpha-olefins in high purity. Aprocess for autothermally cracking a waxy hydrocarbon feedstream toproduce olefin feeds is disclosed in US Patent Application No.20090131731A1, herein incorporated in its entirety by reference.

In one embodiment, the olefin feed may be from a FCC unit or a coker. Inother embodiments, the olefin feed may be from a wax cracker, such as anautothermal cracking reactor. Olefins are typically produced inpetroleum refineries using either the FCC process, the delayed cokingprocess, or less often the fluidized coking process. In the future, asmore waxy feeds become available from new sources (such as fromFischer-Tropsch processes such as Gas-to-Liquid, Coal-to-Liquid, orBiomass-to-Liquid), wax crackers will become more economic. FCC unitsuse a fluidized catalyst system to facilitate catalyst and heat transferbetween a reactor and a regenerator. Combustion of coke in theregenerator provides the heat necessary for the reactor. A good overviewof examples of FCC units are described in “UOP Fluid Catalytic Cracking(FCC) and Related Processes”, UOP 4523-7, June 2008; herein incorporatedin its entirety.

A delayed or fluidized coker is an oil refinery processing unit thatconverts the residual oil from a vacuum distillation column or anatmospheric distillation column into low molecular weight hydrocarbongases, naphtha, light and heavy gas oils, and petroleum coke. Theprocess thermally cracks the long chain hydrocarbon molecules in theresidual oil feed into shorter chain molecules. The coke from a cokercan either be fuel grade (high in sulphur and metals) or anode grade(low in sulphur and metals).

The shorter chain molecules produced in a coker are richer in alphaolefin content than olefin feeds from a FCC unit. The high alpha olefincontent in the shorter chain molecules produced in a coker unit formbecause cokers crack primarily by electron-promoted free radicalmechanisms, whereas a FCC unit cracks by proton-promoted acidmechanisms. The shorter chain molecules from a coker also have arelatively high concentration of olefins. The higher the normal-paraffincontent in the feed to the coker unit, the greater the alpha olefincontent of the shorter chain molecules produced in the coker unit. Inone embodiment, an olefin feed from a coker unit are valuable feeds tomake base oil as they are not generally used to make alkylate gasolineblend stock due to their high concentration of alpha olefins.

In one embodiment the coker unit is a delayed coker unit. A delayedcoker unit is a type of coker unit whose process consists of heating aresidual oil feed to its thermal cracking temperature in a furnace withmultiple parallel passes. This cracks the heavy, long chain hydrocarbonmolecules of the residual oil into coker gas oil and petroleum coke.

Delayed coker units may provide a higher content of alpha olefins thanfeeds from a FCC unit. The content of the alpha olefins is dependent onthe normal-paraffin content in the feed to the delayed coker unit. Manyoil refineries have delayed coker units and the shorter chain moleculesproduced in the delayed coker units are not in as high demand forconventional sulfuric or HF alkylation plants or for chemicals, so theiravailability and pricing are favorable. In some embodiments, the shorterchain molecules produced in a delayed coker unit will require a clean-upstep to reduce nitrogen and sulfur-containing hydrocarbons before theoligomerizing step of the process.

Another important feedstock is an isoparaffin. The simplest isoparaffinis isobutane. Isopentanes, isohexanes, isoheptanes, and other higherisoparaffins are also useable in the process of the present invention.Economics and availability are the main drivers of the isoparaffinsselection. Lighter isoparaffins tend to be less expensive and moreavailable due to their low gasoline blend value (due to their relativelyhigh vapor pressure). Mixtures of light isoparaffins can also be used inthe present invention. Mixtures such as C₄-C₅ isoparaffins can be usedand may be advantaged because of reduced separation costs. Theisoparaffins feed stream may also contain diluents such as normalparaffins. This can be a cost savings, by reducing the cost ofseparating isoparaffins from close boiling paraffins. Normal paraffinswill tend to be unreactive diluents in the process of the presentinvention.

In an optional embodiment the resultant alkylated oligomer can behydrogenated to further decrease the concentration of olefins and thusthe Bromine Number. After hydrogenation, the lubricant component or baseoil has a Bromine Number of less than 0.8, for example less than 0.5,less than 0.3, or less than 0.2.

In one embodiment the alkylation conditions include a temperature offrom about 15 to about 200° C., such as from about 20 to about 150° C.,from about 25 to about 100, or from 50 to 100° C.

In one embodiment, the oligomerization conditions include a temperatureof from about 0 to about 150° C., such as from about 10 to about 100°C., or from about 0 to about 50° C.

As discussed elsewhere the oligomerization and the alkylation can occurseparately (in separate optimized zones) or concurrently. In theembodiment where the alkylation and oligomerization occur concurrently,optimum conditions for either reaction may have to be compromised.However, surprisingly the conditions can be adjusted to achieve bothsubstantial oligomerization and alkylation and result in a valuablelubricant base oil or blendstock.

Wt % Normal Paraffins in Waxy Feeds

Quantitative analysis of normal paraffins in waxy feeds is determined bygas chromatography (GC). The GC (Agilent 6890 or 5890 with capillarysplit/splitless inlet and flame ionization detector) is equipped with aflame ionization detector, which is highly sensitive to hydrocarbons.The method utilizes a methyl silicone capillary column, routinely usedto separate hydrocarbon mixtures by boiling point. The column is fusedsilica, 100% methyl silicone, 30 meters length, 0.25 mm ID, 0.1 micronfilm thickness supplied by Agilent. Helium is the carrier gas (2 ml/min)and hydrogen and air are used as the fuel to the flame.

The waxy feed is melted to obtain a 0.1 g homogeneous sample. The sampleis immediately dissolved in carbon disulfide to give a 2 wt % solution.If necessary, the solution is heated until visually clear and free ofsolids, and then injected into the GC. The methyl silicone column isheated using the following temperature program: Initial temp: 150° C.(If C7 to C15 hydrocarbons are present, the initial temperature is 50°C.) Ramp: 6° C. per minute Final Temp: 400° C. Final hold: 5 minutes oruntil peaks no longer elute The column then effectively separates, inthe order of rising carbon number, the normal paraffins from thenon-normal paraffins. A known reference standard is analyzed in the samemanner to establish elution times of the specific normal-paraffin peaks.The standard is ASTM D2887 n-paraffin standard, purchased from a vendor(Agilent or Supelco), spiked with 5 wt % Polywax 500 polyethylene(purchased from Petrolite Corporation in Oklahoma). The standard ismelted prior to injection. Historical data collected from the analysisof the reference standard also guarantees the resolving efficiency ofthe capillary column.

If present in the sample, normal paraffin peaks are well separated andeasily identifiable from other hydrocarbon types present in the sample.Those peaks eluting outside the retention time of the normal paraffinsare called non-normal paraffins. The total sample is integrated usingbaseline hold from start to end of run. N-paraffins are skimmed from thetotal area and are integrated from valley to valley. All peaks detectedare normalized to 100%. EZChrom is used for the peak identification andcalculation of results.

In summary, some of the potential benefits of the processes include,

-   -   Reduced capital cost for hydrotreating or hydrofinishing,    -   Lower operating costs due to reduced hydrogen and extensive        hydrogenation requirements,    -   Potential use of the same ionic liquid catalyst for        oligomerization and alkylation steps,    -   Improved branching characteristics of the product,    -   Increased overall molecular weight of the product,    -   Incorporation of low cost feed (isoparaffins) to increase liquid        yield of high value distillate fuel or lubricant components,    -   Production of a base oil or lubricant component having unique,        high value properties,    -   Upgrading of olefin feeds from a FCC unit or a coker,    -   The ability to make two or more viscosity grades of base oil        with improved properties.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Furthermore, all ranges disclosed herein are inclusive ofthe endpoints and are independently combinable. Whenever a numericalrange with a lower limit and an upper limit are disclosed, any numberfalling within the range is also specifically disclosed.

Any term, abbreviation or shorthand not defined is understood to havethe ordinary meaning used by a person skilled in the art at the time theapplication is filed. The singular forms “a,” “an,” and “the,” includeplural references unless expressly and unequivocally limited to oneinstance.

All of the publications, patents and patent applications cited in thisapplication are herein incorporated by reference in their entirety tothe same extent as if the disclosure of each individual publication,patent application or patent was specifically and individually indicatedto be incorporated by reference in its entirety.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. Many modifications of the exemplaryembodiments of the invention disclosed above will readily occur to thoseskilled in the art. Accordingly, the invention is to be construed asincluding all structure and methods that fall within the scope of theappended claims.

EXAMPLES Example 1 Preparation of Fresh 1-Butyl-pyridiniumChloroaluminate Ionic Liquid

1-butyl-pyridinium chloroaluminate is a room temperature ionic liquidprepared by mixing neat 1-butyl-pyridinium chloride (a solid) with neatsolid aluminum trichloride in an inert atmosphere. The syntheses of1-butyl-pyridinium chloride and the corresponding 1-butyl-pyridiniumchloroaluminate are described below. In a 2-L Teflon-lined autoclave,400 gm (5.05 mol.) anhydrous pyridine (99.9% pure purchased fromAldrich) were mixed with 650 gm (7 mol.) 1-chlorobutane (99.5% purepurchased from Aldrich). The neat mixture was sealed and let to stir at125° C. under autogenic pressure over night. After cooling off theautoclave and venting it, the reaction mix was diluted and dissolved inchloroform and transferred to a three liter round bottom flask.Concentration of the reaction mixture at reduced pressure on a rotaryevaporator (in a hot water bath) to remove excess chloride, un-reactedpyridine and the chloroform solvent gave a tan solid product.Purification of the product was done by dissolving the obtained solidsin hot acetone and precipitating the pure product through cooling andaddition of diethyl ether. Filtering and drying under vacuum and heat ona rotary evaporator gave 750 gm (88% yields) of the desired product asan off-white shinny solid. ¹H-NMR and ¹³C-NMR were ideal for the desired1-butyl-pyridinium chloride and no presence of impurities was observedby NMR analysis.

1-Butyl-pyridinium chloroaluminate was prepared by slowly mixing dried1-butyl-pyridinium chloride and anhydrous aluminum chloride (AlCl₃)according to the following procedure. The 1-butyl-pyridinium chloride(prepared as described above) was dried under vacuum at 80° C. for 48hours to get rid of residual water (1-butyl-pyridinium chloride ishydroscopic and readily absorbs water from exposure to air). Fivehundred grams (2.91 mol.) of the dried 1-butyl-pyridinium chloride weretransferred to a 2-Liter beaker in a nitrogen atmosphere in a glove box.Then, 777.4 gm (5.83 mol.) of anhydrous powdered AlCl₃ (99.99% fromAldrich) were added in small portions (while stirring) to control thetemperature of the highly exothermic reaction. Once all the AlCl₃ wasadded, the resulting amber-looking liquid was left to gently stirovernight in the glove box. The liquid was then filtered to remove anyun-dissolved AlCl₃. The resulting acidic 1-butyl-pyridiniumchloroaluminate was used as the catalyst for the Examples in the PresentApplication.

Example 2 Oligomerization of 1-Decene

One process for making high quality oils is by oligomerization ofolefins followed by a separate step of alkylation with an isoparaffin.Olefin oligomers exhibit good physical lubricating properties. However,introducing short chain branching in the oligomers enhances theproperties of the final products. Introducing the branching can be doneby alkylation of the oligomers with isoparaffins. Alkylation of theoligomeric products is also a route to reducing the olefinicity of theoligomers and, hence, producing chemically and thermally more stableoligomers. The process is exemplified by alkylation of 1-deceneoligomers (described below).

Oligomerization of 1-decene and alkylation of the oligomer were doneaccording to the procedures described below. In a 300 cc autoclaveequipped with an overhead stirrer, 100 gm of 1-decene was mixed in with20 gm of 1-methyl-tributyl ammonium chloroaluminate. A small amount ofHCl (0.35 gm) was introduced to the mix as a promoter and the reactionmix was heated to 50° C. with vigorous stirring for 1 hr. Then, thestirring was stopped and the reaction was cooled down to roomtemperature and let to settle. The organic layer (insoluble in the ionicliquid) was decanted off and washed with 0.1N KOH. The organic layer wasseparated and dried over anhydrous MgSO₄. The colorless oily substancewas analyzed by SIMDIST. The oligomeric product has a Bromine Number of7.9. Table 1 below shows the SIMDIST analysis of the oligomerizationproducts.

Example 3 Alkylations of 1-Decene Oligomers

The oligomers of 1-decene made as described in example 2 were alkylatedwith isobutane in 1-butylpyridinium chloroaluminate and inmethyl-tributyl ammonium chloroaluminate (TBMA) ionic liquids accordingto the procedures described below. In a 300 cc autoclave fitted with anoverhead stirrer, 26 gm of the oligomer and 102 gm of isobutane wereadded to 21 gm of methyl-tributyl-ammonium chloroaluminate ionic liquid.To this mixture, 0.3 gm of HCl gas was added and the reaction was heatedto 50° C. for 1 hr while stirring at >1000 rpm. Then the reaction wasstopped and the products were collected in a similar procedure asdescribed above for the oligomerization reaction. The collectedproducts, colorless oils, have a Bromine Number of 3.2. Table 1 showsthe SIMDIST analysis of the oligomer alkylation products.

Alkylation of the oligomer was repeated using the same proceduredescribed above, but 1-butylpyridinium chloroaluminate was used in placeof methyl-tributyl-ammonium chloroaluminate. Alkylation of the oligomerin butylpyridinium gave a product with a bromine index of 2.7. TheSIMDIST data is shown in Table 1.

TABLE 1 1-Decene oligomers 1-Decene 1-Decene Alkylation in 1- oligomersSIMDIST Oligomers butylpyridinium alkylation TBP (WT %) ° F.chloroaluminate in TBMA TBP@0.5 330 298 296 TBP@5 608 341 350 TBP@10 764574 541 TBP@15 789 644 630 TBP@20 856 780 756 TBP@30 944 876 854 TBP@401018 970 960 TBP@50 1053 1051 1050 TBP@60 1140 1114 1118 TBP@70 11921167 1173 TBP@80 1250 1213 1220 TBP@90 1311 1263 1268 TBP@95 1340 12871291 TBP@99.5 1371 1312 1315

Example 4 Oligomerization of 1-Decene in Ionic Liquids in the Presenceof iso-Butane

Oligomerization of 1-decene was carried out in acidic 1-butyl-pyridiniumchloroaluminate in the presence of 10 mole % of isobutane. The reactionwas done in the presence of HCl as a promoter. The procedure belowdescribes, in general, the process. To 42 gm of 1-butyl-pyridiniumchloroaluminate in a 300 cc autoclave fitted to an overhead stirrer, 101gm of 1-decene and 4.6 gm of isobutane were added and the autoclave wassealed. Then 0.4 gm of HCl was introduced and the stirring started. Thereaction was heated to 50° C. The reaction was exothermic and thetemperature quickly jumped to 88° C. The temperature in few minutes wentback down to 44° C. and was brought up to 50° C. and the reaction wasvigorously stirred at about 1200 rpm for an hour at the autogenicpressure (˜atmospheric pressure in this case). Then, the stirring wasstopped and the reaction was cooled to room temperature. The contentswere allowed to settle and the organic layer (immiscible in the ionicliquid) was decanted off and washed with 0.1N KOH aqueous solution. Thecolorless oil was analyzed with simulated distillation and bromineanalysis. The Bromine Number was 2.6. The Bromine Number is much lessthan that usually observed for the 1-decene oligomerization in theabsence of isobutane. The Bromine Number for 1-decene oligomerization inthe absence of iC₄ is in the range of 7.5-7.9 based on the catalyst,contact time and catalyst amounts used in the oligomerization reaction.The Simulated Distillation data is shown in Table 3.

The Simulated Distillation data in Tables 1 and 3 show that alkylationsof the already made 1-decene oligomers with isobutane and thesimultaneous oligomerization/alkylation of 1-decene lead to fairlycomparable products. The overall outcome of the two operations isamazingly close in the products boiling ranges and olefinic contents asindicated by bromine numbers shown in Table 2.

Table 2 compares the Bromine Numbers of the starting 1-decene, 1-deceneoligomerization products in the presence of iC₄, 1-deceneoligomerization products without iC₄, and the alkylation products of1-decene oligomers with excess iC₄.

TABLE 2 Oligomerization- alkylation of 1- Oligomerization Alkylated 1-Decene with 10 Products of 1- 1-decene Material Decene mol % iC₄Decene/No iC₄ oligomers Bromine 114 2.6 7.9 2.8 Number

The data above suggests that the chemistry can be done by eitheralkylating the oligomers in situ (where isoparaffins are introduced intothe oligomerization reactor) or in consecutive steps to oligomerizationof an alpha olefin. In both processes, the yielded products are close intheir properties. In the simultaneous oligomerization-alkylation scheme,the desired alkylated oligomeric products can be made in one single stepand, thus, can be an economically advantageous process. However, the twostep process with two separate reaction zones where each can beoptimized independently, provides greater chances for tailoring andtuning the conditions to make products with particularly desiredproperties.

Example 5 Oligomerization of 1-Decene in Ionic Liquids in the Presenceof Varying iso-Butane Concentrations

Oligomerization of 1-decene was carried out in acidic 1-butyl-pyridiniumchloroaluminate in the presence of varying mole % of isobutane. Thereaction was done in the presence of HCl as a promoter (co-catalyst).The procedure below describes, in general, the process. To 42 gm of1-butyl-pyridinium chloroaluminate in a 300 cc autoclave fitted to anoverhead stirrer, 101 gm of 1-decene and 4.6 gm of isobutane were addedand the autoclave was sealed. Then 0.2-0.5 gm of HCl was introduced intothe reactor, and then, started the stirring. The reaction is exothermicand the temperature quickly jumped to 88° C. The temperature droppeddown quickly to the mid 40s and was brought up to 50° C. and kept ataround 50° C. for the remainder of the reaction time. The reaction wasvigorously stirred for about an hour at the autogenic pressure. Thestirring was stopped, and the reaction was cooled to room temperature.The contents were allowed to settle and the organic layer (immiscible inthe ionic liquid) was decanted off and washed with 0.1N KOH aqueoussolution. The recovered oils were characterized with simulateddistillation, bromine analysis, viscosity, viscosity indices, and pourand cloud points.

Table 3, below, show the properties of the resulting oils of different1-decene/isobutane ratios. All the reactions were run for approximately1 hr at 50° C. in the presence of 20 gm of ionic liquid catalyst.

TABLE 3 C₁₀ ⁼/ C₁₀ ⁼/ C₁₀ ⁼/ n C₁₀ ⁼/iC4 = 0.8 iC₄ = 1 iC₄ = 4 iC₄ = 5.5C₁₀ ⁼/iC₄ = 9 TBP @0.5 301 311 322 329 331 TBP @5 340 382 539 605 611TBP @10 440 453 663 746 775 TBP @20 612 683 792 836 896 TBP @30 798 842894 928 986 TBP @40 931 970 963 999 1054 TBP @50 1031 1041 1007 10591105 TBP @60 1098 1099 1067 1107 1148 TBP @70 1155 1154 1120 1154 1187TBP @80 1206 1205 1176 1200 1228 TBP @90 1258 1260 1242 1252 1278 TBP@95 1284 1290 1281 1282 1305 TBP 1311 1326 1324 1313 1335 @99.5

The data shown in Table 3 indicates that the amount of isobutane addedto the reaction does influence the boiling range of the produced oils.As shown in Table 3, there are more products in the lower boiling cutswhen higher concentrations of isobutane are used in the reaction. Thisindicates that more alkylation is taking part directly with 1-decene and1-decene dimers rather than with higher oligomers when higher isobutaneconcentrations are present in the reaction zone. When more isobutane ispresent more alkylation can occur, and 1-decene alkylation with iC₄ tomake C₁₄ and 1-decene dimer alkylation to make C₂₄ will be moreprevalent than at lower concentrations of isobutane. Therefore, thedegree of branching and oligomerization can be tailored by the choice ofolefins, isoparaffins, olefin/isoparaffin ratios, contact time and thereaction conditions.

The alkylated oligomers will no longer take part in furtheroligomerization due to “capping” off their olefinic sites, and the finaloligomeric chain will be shorter perhaps than the normal oligomericproducts, but with more branching. While the oligomerization pathway isthe dominant mechanism, it is very clear that the alkylation of 1-deceneand its oligomers with isobutane does take part in the chemistry.

Table 4, below, compares some physical properties of the productsobtained from the reactions of Table 3.

TABLE 4 C10⁼/ C10⁼/ C10⁼/ C10⁼/iC₄ = C10⁼/iC₄ = 0.8 iC₄ = 1 iC₄ = 4 iC₄= 5.5 9 VI 145 171 148 190 150 Vis@100 9.84 7.507 9.73 7.27 11.14 VIS@4061.27 37.7 59.63 33.5 70.21 Pour −42 −42 −44 −44 −52 Point Cloud −63 −64−66 −69 −28 Point Bromine 3.1 0.79 2.2 3.8 6.1 Number

The oligomerization/alkylation run @ 1-decene/iC₄ ratio of 5.5 wasrepeated several times at the same feed ratios and conditions. Theviscosity@100° C. in the repeated samples ranged from 6.9-11.2 cSt. TheVI ranged from 156-172. All the repeated samples contained low boilingcuts (below 775° F.) ranging from 10%-15%. The low boiling cut appearsto influence the VI.

The Bromine Numbers shown in Table 4 are much less than usually observedfor the 1-decene oligomerization in the absence of isobutane. TheBromine Number for 1-decene oligomerization in the absence of iC₄ is inthe range of 7.5-7.9 based on the catalyst, contact time and catalystamounts used in the oligomerization reaction. Table 5, below, comparesthe Bromine Number analysis of 1-decene, simultaneous oligomerizationand alkylation of 1-decene, 1-decene oligomerization only products, andthe alkylated oligomers (oligomerization followed by alkylation). Bylooking at these values, one can see the role of the incorporation ofisobutane on the olefinicity of the final products.

TABLE 5 Oligomerization Alkylated 1- with 10 mol % 1-Decene decene 1-iC₄, (20 mol % Oligomeri- oligomers with Material Decene iC₄) zation iC₄Bromine 114 6.1, (2.2) 7.9 2.8 Number

Example 6 Oligomerization of a Mixture of Alpha Olefins in the Presenceof iso-Butane

A 1:1:1 mixture of 1-hexene:1-octene:1-decene was oligomerised in thepresence of isobutane at the reaction conditions described earlier foroligomerization of 1-decene in the presence of isobutane (100 gmolefins, 20 gm IL catalyst, 0.25 gm HCl as co-catalyst, 50° C.,autogenic pressure, 1 hr). The products were separated from the ILcatalyst, and the IL layer was rinsed with hexane, which was decantedoff and added to the products. The products and the hexane wash weretreated with 0.1N NaOH to remove any residual AlCl₃. The organic layerswere collected and dried over anhydrous MgSO₄. Concentration (on arotary evaporator at reduced pressure, in a water bath at ˜70° C.) gavethe oligomeric product as viscous yellow oils. Table 6 below shows theSimulated Distillation, viscosity, and pour point, cloud point, andbromine number data of the alkylated oligomeric products of the olefinicmixture in the presence of isobutane.

TABLE 6 Oligomers of SIMDIST C₆ ⁼, C₈ ⁼, C₁₀ ⁼ W/iC₄ TBP (WT %), ° F.TBP @0.5 313 TBP @5 450 TBP @10 599 TBP @15 734 TBP @20 831 TBP @30 953TBP @40 1033 TBP @50 1096 TBP @60 1157 TBP @70 1220 TBP @80 1284 TBP @901332 TBP @95 1357 TBP @99.5 1384 Physical Properties: VI 140 VIS@100° C.7.34 CST VIS@40° C. 42 CST Pour Point −54° C. Cloud Point <−52° C.Bromine # 3.1

As shown in the data above, high quality oils with desirable lubricatingproperties can be made by either simultaneous olefinoligomerization/alkylation, or by oligomerization of the appropriateolefins followed by alkylation of the oligomeric products. Regardless ofthe process, the oils produced in both processes appear to be close intheir boiling ranges, olefinicity and physical properties such asviscosity indices, viscosities, pour points and cloud points. Bothprocess lead to oils with appreciable concentrations of branchedparaffins formed by capping (alkylating) olefins and their oligomers andlow olefin concentrations.

Example 7 FCC Naphtha

A sample of a naphtha produced at Chevron's Pascagoula FCC unit wasanalyzed and determined to have the hydrocarbon types summarized below:

TABLE 7 Hydrocarbon Types Wt % N-Paraffins 4.560 Iso-Paraffins 23.674Naphthenes 7.900 Olefins 29.111 Aromatics 34.755 Total 100.000

This sample of FCC naphtha had a range of C5 to C15 olefins. The olefinswere both alpha olefins and internal olefins. There were a higher amountof internal olefins than alpha olefins. Additionally, the FCC naphthahad a range of C5 to C14 isoparaffins.

A separate sample of FCC gas from a recent pilot plant FCC unit run hada mix of C2 to C7 olefins and C3 to C7 isoparaffins.

The broad range of olefins with different carbon numbers and olefinplacement make the olefins from a FCC unit useful in the processesdescribed herein.

1. A process to make two or more viscosity grades of base oil,comprising: a. alkylating and oligomerizing an olefin feed produced bythermal cracking of a waxy feed with an acidic ionic liquid catalystcomprising a chloroaluminate in a common oligomerization-alkylation zoneto produce an alkylated oligomeric product; and b. separating out two ormore viscosity grades of base oil from the alkylated oligomeric product,wherein at least one of the two or more viscosity grades of base oilhas: i. a kinematic viscosity at 100° C. of 6.9 mm2/s or greater, ii. aVI of at least 134, iii. a Bromine Number of less than 4, and iv. acloud point less than −30° C.
 2. The process of claim 1, wherein a setof alkylation conditions in the alkylation zone are selected to optimizea yield of one of the two or more viscosity grades of base oil.
 3. Theprocess of claim 1, wherein the olefin feed is from a FCC unit, a coker,or a wax cracker.
 4. The process of claim 1, wherein the acidic ionicliquid catalyst comprises a 1-butyl-pyridinium chloroaluminate.